Electronic counting tube



Feb. 12, 1957 G, E, HAGEN 2,781,171

ELECTRONIC COUNTING TUBE Filed Sept. 17, 1948 5 Sheets-Sheet 1 nuoeesceur sceeau IINVENTOR. .Gl'N/V 6 M466 Feb. 12, 1957 G. E. HAGENELECTRONIC COUNTING TUBE 5 Sheets-Sheet 2 Filed Sept. 17, 1948 INVENTORTOQA/Ey E ,7 H Llau :52 f i eve 0 $000 GLEN/V 6. HAG6 N Feb. 12, 1957 e.E. HAGEN ELECTRONIC COUNTING TUBE 5 Sheets-Sheet 3 Filed Sept. 17, 194814K lB ZZ O 5700 2 LEAD e/Na LAD

AUX/[M29 QING L/JD INVENTOR.

w. y m w m. N M 6 \&

INVENTOR. 'GZE/VA/ 5. #466 5 Sheets-Sheet 4 flrro ug E G. E. HAGENELECTRONIC COUNTING TUBE Feb. 12, 1957 Filed Sept. 17, 1948 1957 e. E.HAGEN ELECTRONIC COUNTING TUBE 5 Sheets-Sheet 5 Filed Sept. 17, 1948 raw7 PUL$ OUTQQUT LIA/E 47 OUTPUT TUBC' P. 2 J

54 Hfi47 (50 55 v u M O J 2 6 00 M55 4 a F5 www MU 4 F wm United StatesPatent ELECTRONIC COUNTING TUBE Glenn E. Hagen, Redondo Beach, Calif.,assignor to Northrop Aircraft, Ina, Hawthorne, Calitl, a corporation ofCalifornia Application September 17, 1948, Serial No. 49,755

1 Qlaim. (Cl. 23592).

My invention relates to electronic counters, and more particularly to anelectronic counter tube and counting circuit.

Among the objects of the invention are:

To provide an electronic tube having a plurality of stable states;

To provide a circuit for such a tube whereby it can be used as anelectronic counting device;

To provide a multi-stable state electronic tube and circuit suitable forcounting and which will give a visual indication of the count;

To provide electronic counters in which the basic element is anelectronic counting tube;

And to provide a simple efiicient electronic tube suitable for digitalcounting.

In broad terms, the tube of the present invention has as many stablestates as the number of digits of the number system being used. Meansare provided to shift the tube from one stable state to the next inorder, with a carry pulse being produced when the tube goes from thestable state corresponding to the largest digit to that corresponding tothe smallest digit and vice-versa. Such tubes can be interconnected toincrease the number of significant figures available.

My invention can he more readily understood by reference to thedrawings, in which:

Figure l is a diagrammatic perspective view of a cathode-ray tubeincorporating the present invention, the envelope being partially cutaway.

Figure 2 is a plan view of the digit plate assembly of the tube shown inFigure l.

Figure 3 is a wiring diagram of the tube of Figure 1.

Figure 4 is a diagram used as a symbol representing the tube of Figure1.

Figure 5 is a wiring diagram showing the use of several tubes, as shownin Figure l, to increase the number-of significant figures that can becounted.

Figure 6 is a diagram of voltage changes in the circuit of Figure 5.

Figure 7 is a wiring diagram showing how a number can be transferredfrom one counter to another and to retain that number in the originalcounter.

Figure 8 is a wiring diagram of the pulse source used in the diagram ofFigure 7.'

Figure 9 is a wiring diagram of the gates used in the diagram of Figure7.

Referring first to Figure l, which shows diagrammatically in perspectivethe structure of a preferred counting tube. built for and operable tocount in the decimal system,

in accordance with the present invention, a glass envelope 10 of theusual cathode-ray tube shape, is provided at theelectron beam, and anysuch arrangement, termed here.-

in an electron gun, will be suitable for use in the tube to be describedherein.

Patented Feb. l2, i957 Thus, cathode 12 and accelerating electrode 13-represent an electron gun for generating a beam of electrons and forprojecting this beam along the axis of the tube, if undeflected.

Shortly after the electron beam leaves the gun, a pin rality ofdeflecting plates Ga to 9a, inclusive, are arranged around and spacedfrom theaxis of the tube, each having a lead iii: to 912, respectively,passing through envelope 10. Thus, ten deflecting plates and leads areprovided.

Farther toward the large end of the tube, a control ring 14 is heldconcentrically around the axis of the tube by a ring lead 15, andadjacent the large end ispositioned a digital plate assembly 16positioned normal to the tube axis. Digital plate assembly 16 consistsof ten coplanar side-by-side spirally wedge shaped digital plates 0 to9,.inelusive; the digital plates are insulated from each other andeachis provided with an envelope lead lie to 9c, re-

spectively. The platesdo not meet at the. axis of the tube but stopshort of the axis to form a central plate assembly aperture 17, and thecurvature of the digital plate edges is such that all radii of the tubewill intersect threev plates. Each plate has a small beam aperture 18between the inner and outer limit of the plates.

Thus, ten digital plates are provided, representing the digits 0 to 9,.inclusive, together with their exten'or'leads. Between plate assembly 16and the large end of the tube, a cross bar 20- is extended normal to theaxis of the tube, this bar having an exterior bar lead 21. From thisbar, a control stud 22 is axially extended toward the cathode of thetube through plate assembly aperture 17 to a point slightly on thecathode side of control ring 14. The large end of thetube is providedwith a fluorescent screen 24 of conventional type, on the insidethereof. As is customary, the tube is evacuated and sealed.

Various electrical connections to the tube just above described forestablishing static states herein are shown in Figures 1, 2, and 3. Thedigital plates 0 to 9, inclusive, are supplied .by a positive potentialthrough a plate voltage line 25 carrying a positive potential, this linebeing connected to each digital plate through a plate load resistor 26..In practice, this load resistor can be a carbon ring of the properthickness to give the desired resistances and attached to the digitalplates 0-9, inclusive, on the screen side of the ring and to the platevoltage line 25 on the other side thereof. However, for simplicity ofillustration, each digital plate is shown as connected to the platevoltage line 25 through a separate resistor.

Each plate 0 to 9, inclusive, is also connected to a correspondingdeflecting plate in the group. 0a to- 9a, inclu sive, through adeflecting plate resistor 27 but -the particulardeflecting. plate towhich a particular. digital plate is connected is on the opposite sideof the tube, as-shown in Figure 1. The deflecting plate resistances 27are of such high resistance that each deflecting plate will always be,of a lower positive potential than that of the digital plate to whichthe deflecting plate is connected.

Each deflecting plate is also connected to the electron gun cathodethrough a cathode resistor 29. The corn-v plete resistance network ofthe tube is shown in Figure 3.

Two special output leads are also brought directly out from thetube, onelead 3.0 from the digital plate .0,

corresponding to the smallest digit, and one lead 31 from. the digitalplate 9, corresponding to the largest digit,.

both leads lay-passing the plate load resistors. When other radices areutilized, the smallest digit and largest digit connections will likewisebe brought out. In this regard, while the decimal number system, hasbeen chosen herein for explanation purposes, the tubes and circuits willbe similar for any number system, as long as, the

radix is small enough to allow the plate assembly of the counting tubesto beproperly segmented.

barb. The control stud 22 is represented by an axial line alongside ofthe barb. Only. two digital plates areshown, i. e., the plate and the 9plate as these leads are the only output leads. The lead 30 from thedigital plate 0 leaves from the left of the symbol, and the lead 31 fromthe digital plate 9 is on the rightof the symbol. .The plate voltageline 25 is shown as connected to both digital plates 0 and 9 through thedigital plate resistors 26. In case an additional control ring 14a isneeded, this will be represented by a barb positioned below the barb forring 14.

Considering the tube of Figure 1 project a beam of electrons through thetube, this beam will pass between the deflecting plates 0a to 9a,inclusive, between the control ring 14 and the control stud 22, and willland at random on one of the digital plates 0-9 in-the digital plateassembly. The resistances 2'6, 27, and29 are so proportioned that theelectron beam will have a stable position on whatever digital plate itfalls on, with the beam falling on a digital plate at the position ofthe associated beam aperture 18. These stable states, with the beam in aparticular position on one particular plate, are obtained because thebeam electrons form a substantial part of the beam not passing throughaperture 18 collect on the particular plate making it more negative andthus unbalances the combined field of the deflecting plates to deflectthe beam to the proper position on the digital plate the beam iscontacting. In the absence of additional deflecting forces the beam willstayon any digital plate it impacts, and will stay, under these sameconditions, in the general area of aperture 18 on-each plate.

Asa portionof the beam normally passes through aperture 18, there willbe a luminous spot produced on the fluorescent screen when the beam ison any digital plate, thereby providing a visual indication of where thebeanris within the tube,-so that a visual indication of the count withinthe tube can be seen at all times.

An alternate method of obtaining a visual indication of beam position isto coat the cathode side of the digital plates with fluorescent materialand observe the lumi nous spot position by'a conical mirror positionedon the cathode side of'the diigtal plates and viewed through the centraldigital plate assembly aperture 17. When a beam aperture 18 is used ineach digital plate, the size and intensity of the spot on thedigitalplate is to be energized to adjusted so that the part of the beamabsorbed by the plate is suflicient to lower the potential of theconnected deflecting plate, and the part passing to the fluorescentscreen is suflicient to cause a luminous spot thereon.

' When the counter tube as described is first energized, the beam willrest on one of the digital plates. but on no particular one. For thisreason. unless the beam happens to be on digital plate 0, a single shortnegative pulse is'initiallv applied to the digital plate 0 lead 30 ofthe tube which 'causes a drop in potential on the deflecting plate nopposite the digital plate 0. This causes the electron beam to bedeflected so that it termin'ates .on the digital plate 0 directly overits beam aperture 18. This will be called point P as shown in Figure 2.When the tube is in this stable condition, a

7 positive inputpulse, applied to the. control ring 14 of the tube, willcausetheselectron beam to move outwardly,

one input pulse has resulted in the'number in the counter to increasefrom 2909 to 2910. This shift in tube 13 does'.

and travel from point P to point P as shown in Figure 2, point P beingon digital plate 1. As long as the positive pulse on'the ring lasts, thebeam will stay at point P because of deflection by ring 14 and becausethe voltage change on deflecting plate 1a caused by the absorption ofthe beam on plate 1 causes the deflecting plate 1a opposite digitalplate 1 to be of lower positive potential than the other deflectingplates, thereby holding the beam on digital plate 1. When this positivering pulse ends, however, the beam will move inwardly to its stableposition on digital plate 1, i. e., to. point P which is at the beamaperture 18 in digital plate 1. The next positive pulse applied tocontrol ring 14 will move the beam to digital plate 2, and so on aroundthe digital plate assembly in'additive direction, in accordance with thenumber of positive pulses applied to the control ring If, however, thefirst pulse applied to control ring .14 after positioning the beam ondigital plate 0 is negative, then the terminus of the electron beam onthe digital plate assembly will change from point P1 on digital plate 0to point P4 on digital plate 9. When the negative ring pulse ceases, thebeam will remain on digital plate 9 but will return to point P5 on thislatter plate, point P5 being the beam aperture 18 position, and thestable position of the beam on digital plate 9. V 7

Thus, positive pulses to control ring 14 will cause additive counting,whereas negative pulses on this same ring; will cause subtractivecounting.

Exactly the same effect will be caused by applying nega tive pulses tocontrol stud 22 for additive counting, and applying positive pulses tostud 22 for subtractive counting. However, for circuit separation, it isconvenient to use both control electrodes for beam control. So that thebeam can be spotted on anyplate desired, each plate is provided with asetting lead 38.

To increase the number of significant figures available in a counter,more than one tube, such as that just described, is used. Figure 5 is adiagram showing one type of counting circuit utilizing the abovedescribed counting tube, the symbols for which are as described forFigure 4. In this diagram, the digital plate 9 lead 31 and the digitalplate 0 lead 30 of one tube are connected to the control ring 14 andcontrol stud 220i the next tube with a condenser 40 placed in eachconnection. Two resistors 41 and 42 are placed in series across theseconnections on the ring and stud side of condensers 40 with a groundedtap 43 between the resistors 41 and 42, each resistor being providedwith a voltage adjustment 43a.

Assume that the numbers in the first four tubes A, B, C, and D, as shownin Figure 5, are set to be 9, 0, 9, and 2, respectively. This setting isdone by applying a negative pulse to the particular plates in theparticular tubes through the appropriate setting lead 3S or leads 30 or31.- Thus, the number'2909 is set up in the counter. Also assume thatadditive counting is taking place, i. e., that positive pulses are fedinto the control ring input lead 15 to tube A. As indicated in Figure 6,the voltage at the digital plate 9 lead 31 in tube A of Figure 5 will beon the lower portion of the solid line (marked X) since the number 9 isin tube A; also the voltage at digital plate 0 in tube A of Figure 5 isindicated by the upper dotted line (marked Y) in Figure 6. The nextpositive input pulse at the ring input lead 15 to tube A causes theterminus of the electron beam to switch from the nine s'eg-' ment to thezero segment of tube A and thereby cause the voltage at point X toincrease, and the voltage'at point Y of Figure 5 to decrease anindicated by the crossing solid and dotted lines in Figure 6. Thisvoltage difference across resistors 41 and 42 following tube A of Figure5, when placed across the control ring lead 15 and control stud 'lead 21in tube B, is sufficient to cause the number in tube B to increase fromzero to one.- Thus,

5 not cause any action in tube C because no beam shiftoccurred'betwee'rr digitalplates'il and-9 in tubeB'.

Again, assume that'the numbers 0, 0, and 1 are in tubes A, B, C, and D;respectively, of the counter. in Figure-5 (representing the number 1000)and that 'subtractivecounting is taking place. When either a negativepulse appears at thering input lead of tube A or a positive pulseappears at stud input lead 21 of. tube A, the electron beam will shiftfrom the digital plate 0 to the digital plate 9'in tube A. In' doing so,the voltages at thedi'gital plates 0 and 9 of tube A will be similar butopposite to the Voltagesindicated by X and Y in Figure 6; As a result, avoltage will appear across resistors 41 and 42 following tube A inFigure 5 of such magnitude and such polarity that it causes tube B to beswitched from zero to' nine. Tube B repeats the action and switches tubeC from zero to nine, and this causes tube D to be switched from one tozero. Thus, the number in the counter has been changedlfromanoriginalvalue of 1000 to; a value of 0999 by an input of one subtractive pul'se.The system of Figure 5 will, therefore, count pulses additivelyor'subtractively applied to the input of tube A.

The circuit shown in Figure 7 can be used to'transfr a number from onecounter to another, and still retain that number in the originalcounter.

Four counter tubes .L, M, N, and O are set upto. count as shown inFigure 5. These counter tubesarethe same as has hereinbefore beendescribed, with the single exception that an auxiliary control ring 14ainsertedin each. tube just below ring 14. Ring 14a acts exactly the sameas ring 14 to move the electron beam, and is used separately becaus'ecircuit separation is needed.

The digital plate 9 of each tube L, M, N, andO isprovide'dwith a gatelead 45, the gate leads from tubes L,.M, N, and 0 connecting with gates61, G2, G3. and 64, respectively. Each gate is also, providedwith apulsesource lead 46 connected to a pulse source line 47. Line 47 is energizedby a pulse source PS, this pulse source being under the control of atransfer pulse input 48. Circuits for both gate and pulse sources willbe describedlater. Pulse source line 47 also energizes the auxiliaryrings 14a through auxiliary ring leads 49.

Each gate G1, G2, G3 and G4 is provided with an output line a. Theselines 45a run from the respective gates to the stud leads 21 of a secondbank of counter tubes P, Q, R, and S, respectively. 7 Tubes P, Q', R,and S are the same as those used in the circuit of Figure 5,110auxiliary ring being needed. Tubes P,'Q, R, and S are also connected asshown in the circuit of Figure 5, withthe single exception of theprovision of a time delay device D between each set of resistors 41 and42 and the ring lead 15 and stud lead 21 of the following counter tube.This delay device may be. of the acoustical type such as, for example,the crystalmercury delay device well known in the art. It willv benotedthat when hooked up as above described,,the-stud of each tube P, Q, R,and S is connected both to the respective gate and to the output of thepreceding tube.

The first tube L of the bank L, M, N, and O is pro.- vided with countinginput leads 15 and 21 going to the ring 14 and stud 22 of tube L,respectively, and they first tube P of the tube bank P, Q, R, and S inalso provided with counting input leads 15 and 21, respectively,connected to the ring 14 and stud 22 of tube P.

From the above description of the circuit of. Figure 7, it will be seenthat when gates G1, G2, G and G4 are open and the puise source PS is notoperating, any-four digit number desired. can be set up in tube bank 1.,M, N, and 0 and any four digit number desired can also be set upin tubebani: P, Q, R, and S through their respective counting input withoutinteraction between the banks, as thisinteractio'n can take place onlywhen the pulse source circuit is initiated bya transfer pulse. 7 V

The pulse source PS used in the circuit of Figure 7 is shown in Figure.8. MV representsan oscillator, pulse forming circuit such "as, forexample, a multivibrator, This. multivibrator runs continuousIy and"its; output is applied to the cathode 50 of a cryst'al diode 51 throughcathode wire 52'. Resistances 53 and'54 have one end connectedtogetherand'to cathode wire 52. Resistance 53 is connected at the other end to asource of positive potential, and.thejother end of resistance 54 isgrounded. These-two resistances 53 and 54 maintain the dii'ectcurrentvolt'age level'of the cathode 50'0f the diode constant; The plate 55 ofthe diodeis connected to the output line 47'of the pulse. source PS,and'plate resistances 57 andJ'SS are connecteditog'ether-at one end andto output 'line 47. The: other end of plate. resistor 57 is connectedto, the digital'plate Gof'a pulse source counter tube60. similar to thatshown in Figure 1', and the, other end. of. plate resistor 58 isgrounded; Plate resistors 57 and 58. serve to maintain the directcurrent. voltage level of. the-plate 55' of thediode at one of'twovalues. Thesevalues are a determined" by the'condition of the digitalplate 0 'off'the pulse source counter tube 60. Ring 61 of the pulsesource countertube 60 is connected to transfer pulse input wire 48, thislatter wire also being connected to output line wire 47 of the pulse.source.

When the beam of the pulse source counting tube. 60 is on. its digitalplate 0, the. positive voltage at the top of plate resistance 57 issufficiently low that the voltage at the plate 55' of the diode isalways below that of the cathode 50; thus, no pulses pass from themultivibrator through the diode to the pulse output line wire 47. Asingletransfer pulse applied to input wire 48 will switch the countingtube from zero to one and also this pulse will'feed directly to theoutput line 47 of the pulse. source. By switching the counting tube fromzero to one, the. voltage of the plate of the crystal. diode is caused.to, rise, thereby allowing pulses from the multivibrator to pass throughthe diode to the output line 47. However, each pulse that passes throughthe crystal diode is also fed back into the ring 61 or" the pulse sourcecounting tube 60 and causes the pulses to be counted therein as they.pass to the output of the pulse source. After nine pulses from themultivibrator have passed to the output l:ine.47-,v the pulse sourcecounting tube 6% will be back to zero and immediately the crystal diodewill block further. output from the multivibrator. Thus, ten pulses haveappeared at the pulse source output line 47; one from the initialtransfer impulse applied to inputwire 48 and. nine from themultivibrator MV. These ten pulses. ap,-. pear all along pulse outputline 47 at the gate inputs 46. One of the gates G1, G2, G3 or G4 used inthe counting circuit illustrated in Figure 7 is shown in Figure 9. Thedigital plate 9 of meet the counter tubes L, M, N, or O, is connected bygate lead 45 to the grid of a'vacuum tube 71 through a direct currentblocking condenser 72.. Grid 70 is connected to the tube cathode 73through grid. return resistor '74 and biasing resistor 75, the latterbeing shunted by capacitor 76. Anode 77 is provided with the.

usual positive potential.

A load resistor '78 is connected to grid return resistor 74 and biasresistor 75 and the other end of the load resistor '78 is grounded.Potentials developed across load resistor 78 are applied. to a detectorgrid 80 of a second.

tube 81 through input condenser 83 and to the cathode 82 of said lattertube, detector grid 80 being providedv with a return resistor 84 havinga high resistance. Pulse.

source lead 46 is connected to an input grid 86 in second tube 81, thelatter, being provided with an output resistor- PS via line 47 and theoutput 45a of the gate goes toa stud in one of the tubesv P, Q, R, or S.

Tube 71 is. operated near cut-0d for the tube. Thus,

negative pulses. arriving at the. grid 70 of this tube-from.

the digital plate 9 of the counting tube to whichthis grid:

is'connected merely drive the tube '71 below cut-ofi and are of noconsequence. 1 V. f c a When the counting tube to which the first tube71 of the gate is connected goes from the number eight to. nine,

for example, the gate is unaffected and second tube 81 is able toconduct. However, when the number in this counting tube increases fromnine to zero, a positive pulse is applied to the grid 70 of tube71,and.tube 71 momentarily conducts; the blocking condenser 72preventing a long lasting direct current positive voltage from beingimpressed on the grid of tube 71. When tube 71 conducts, it" energizestube 81 through input condenser 83, and places a positive pulse on thedetector grid 80 of second tube 81.. As this grid 80 of tube 81is.driven positive, it starts to draw current. When the positive pulse onthe grid 80 ofsecond tube 81 is terminated, this grid 80 will be at amore negative voltage than it was under initial conditions, due to thegrid current. This negative voltage is slowly eliminated by a leakagecurrent through return resistor 84, but the high resistance of returnresistor the number in the counting tube L, M, N, or O switches fromnine to zero and which then closes, i. e., is not capable of conducting,and remains closed until after the counting tube of the connectedcounter tube of Figure 7 hasbeen cycled with ten pulses from the pulsesource PS.

* The action of the circuit shown in Figure 7, including the circuitsshown in Figures 8 and 9, as used to transfer a number from tubecounters L, M, N, and O to tube counters P, Q, R, and S, and to retainthat number in tube counters L, M, N, and O, is as follows: i r

Assume that counter tubes L, M, N, and have th numbers 5, 9, 0, and l(1095) respectively placed in them, and that tubes P, Q, R, and S allhave the number zero in them. Note that there is an unbroken lead from apulse source, PS, to the auxiliary rings 14a of tubes L, M, N, and O ofthe first counter. Also a lead is available from the pulse source PS togates G1, G2, G3, and G4, whose inputs are connected to the digitalplate 9 leads of tubes L, M, N, and 0, respectively. The outputs of thegates G1, G2, G3 and G4 pass to the studs of tubes P, Q, R, and S. Theoutput of the pulse source PS is bursts of ten positive pulses. Thedelay devices D, located between each counting tubes P, Q, R, and S,will permit carry pulses between these tubes to pass only after thepulse source has completed its cycling of the first counter.

The gates G1, G2, G3, and G4 are open, i. e., capable of conducting totheir respective tubes P, Q, R, or S. A transfer pulse is applied totransfer pulse input 48 to start the pulse source operating. This firstoutput pulse from the pulse source, through the auxiliary ring 14aconnections, increases the number in tube L from to 6, increases thenumber in tube M from 9 to 0 and thereby closes gate G2, increases thenumber in tube N from 0 to l, and increases the number in tube 0 from 1to 2. Since all of the gates were initially open to pass pulses from thepulse source to tubes P, Q, R, and S, one suotractive pulse (a positivepulse to the stud) has also been fed to tubes P, Q, R, and S through thegates. Consequently, the second counter now reads 9999. However, whentube M goes from 9 to 0 it closes gate G2 and therebyprevents furthersubtractive pulses from entering tube Q. Gate G2 will remain closeduntil after the first counter has been completely cycled with tenpulses.

' Normally,'when tube M increased its number content from 9 to 0, acar'rypulse-would be passed to the next tube N through the condenser 40,40a and resistor 41, 42 network. However, the time constant of thisnetwork between-each of the tubes L, M, N, and O'ca'n be suit ablydesigned such that the carry pulse from a preceding tube such'as M, thatwas initiated in tube M by apulse from the pulse source PS, arrivesinthe following tube, such as N, at substantiallythe sanie time; as thepulse from the pulse source arrives in tube N. j V T p Thecarry. pulseand the pulse from the, pulse source are thus virtually superimposed andtube Niwill not recognize the carry pulse as such, separate from thepulse from the pulse source.- The fifth pulse from the pulse source willswitchtube L from'9 to 0 and closev gate G1. The ninth pulse from. thepulsesource will switch tube 0 from 9 toil and close gate G4. The tenthinput pulse willswitch tube N from 9 to 0 and close gate Ga. 1

As a result of cycling each tube L, M, N, and .O of the first counterwith ten pulses, and .by designing the carry pulse forming circuit sothat carry pulses as such are not recognized in any of the tubesof thefirst counter when the pulse source is operating, the number 1095 willbein both counters. Tube P has counted backward-from Zero to five; tubeQ has counted backward from zero to nine; tube R has countedbackwardfrom 'zero to zero; "and tube S hasicounted backward from'zeroto one. If the number 1095 is, transferred again. from the first counterto the second, the carry pulses from tube P to tube Q and from tube R totube S will be delayed and will take place after the cycling of thefirst counter, which gives 2190 in the second counter. r v Sincethesecond counter has each tube counting backward,the carry pulses will beof a subtractive nature. Therefore, the carry pulse leads 30 and 31 arereversed in the second counter,.i. e., instead of connecting the digitalplate 9 of one tube to the. ring of the next and the digital plate 0 ofthe first tube to the stud of the second, the digital plate .0 of thefirst tube is connected to the ring of the second and the digital plate9 of the first tube is connected to the stud .of the second. This typeof connection has been made in Figure 7. a a i If the inputs from thefirst counter to the second counter were to be reversed and applied tothe rings of. each counting tube P, Q, R, and S instead of to the studsas shown 'in Figure 7, the number in the first counter would'betransferred negatively to the second. In this latter case, the carrypulse leads in the second counter would have to be reversed again. Thecounting tube described above and the associat counting circuits shownherein offer the advantages of highspeed electronic counting without thedisadvantage of using a multiplicity of tubes to secure a fewsignificant figures. Since an ordinary electron tube has only two stablestates, i. e., non-conducting or conducting, a great many tubes arenecessary to have a counter with any sizable number capacity. A singleelectron tube with many stable states as described herein alleviatesseveral difiiculties inherent with the use of many electron tubes, i.e., probability of tube failure, large power requirements, a change inthe radix of the number system used, etc.

What is claimed is: s In combination with a plurality of electroniccounting tubes each having as many stable states as there'are digits inthe number system being counted, each having input.

means when energized to serially shift said tube from one stable stateto the next in either direction and each having output means forproducing a pulse when passing between the stable state representing thesmallest digit and the stable state representing the largest digit, afirst bank of tubes representing a plurality of significant figures, theoutput of each of said tubes being connected to the next by means fordiscriminating the direction of the pulse in said output means to theinput means of the next tube to cause said tube to shift its stablestate in the proper direction, means, for applying additive orsubtractive pulses to the first tube in said first bank to causecounting in all significant figure tubes, a second bank of similar tubesrepresenting the same plurality of significant figures and connected tocount as recited for said first bank, each tube of said first bank beingconnected to cause the tube in the second bank of tubes representing thesame significant figure to count, a gate in each of said latterconnections, a pulse source having an output, means for limiting onecycle of pulses from said source to a number corresponding to the numberof stable states in each tube, the output of said pulse source beingsimultaneously connected to the input of each tube of said first bank oftubes, means operated by shift of the stable state in each tube of thefirst bank to the stable state representing the largest digit to rendersaid gates nonconducting, the discriminating means between each tube ofsaid second bank being provided With a delay device to provide time forone complete cycling of each tube of said first bank with pulses fromsaid pulse source before energizing the following tube in said secondbank whereby a number counted in said first bank is transferred to saidsecond bank with retention of the number transferred in said first bank.

References Cited in the file of this patent UNITED STATES PATENTSRichardson Oct. 31, Mertz Jan. 2, Shelby Mar. 12, Hanscom Dec. 10,Little Sept. 8, Hadekel Oct. 31, Skellett Feb. 19, Snyder July 16,Morton et a1. Aug. 10, Munster Jan. 4, Rosen July 26, Overbeck Nov. 15,Llewellyn Feb. 7, Moon May 20,

FOREIGN PATENTS Great Britain June 30,

